Genuine BMW 335i Ignition Coil

BMW 335i Ignition Coil Parts Questions & Answers

• IGNITION COIL
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  Q: How Does the Distributorless Ignition System and Ignition Coil in Engines Work?

  A: All engines use a distributorless ignition system with individual ignition coils (numbered) for each cylinder. There is no distributor cap or ignition rotor. Each coil is separately controlled and monitored by the ECM. When the ignition is switched ON, the ECM receives wake-up (KL 15w) via the bus network and a hardwire KL15 wake-up signal directly from the car access system (CAS) to energize the ECM main relay and other DME relays to supply power to the engine electronics fuse carrier and to the ignition coils. Maintain cleanliness when servicing ignition coils. Fuel and oil residue can cause a breakdown in the electrical resistance of the silicone encased coil, resulting in ignition coil failure. Ignition timing is electronically mapped and not adjustable. The ECM uses engine load, engine speed, coolant temperature, knock detection, and intake air temperature as the basic inputs for timing control. A three-dimensional map similar to the one shown is digitally stored in the ECM. The initial ignition point is determined by the Crankshaft Position Sensor during cranking. Once the engine is running, the ECM adjusts ignition timing based on operating conditions.
• Ignition Coil
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  Q: How do you remove and install an ignition coil?

  A: Make sure the ignition is switched OFF. Remove the ignition coil cover. Unlock the ignition coil connector and pull the connector off the coil. Slide the rod-shaped ignition coil straight out of the spark plug hole. Be cautious to maintain cleanliness when servicing ignition coils. Fuel and oil residue can cause a breakdown in the electrical resistance of the silicone encased coil, resulting in ignition coil failure. Installation is the reverse of removal. Check for fault codes and reset ECM memory.